that's one thing that pete williams from nbc news was insistent all the way through, that his law enforcement sources, which, of course, are impeccable were saying that there was not a suspect in custody. what was going on yesterday and what continues to go on today is that authorities have pored through the video and pictures have been coming in over the last three days trying to pinpoint exactly where those two packages were placed before they went off. now, authorities do acknowledge to nbc news that they have identified by sight a person who is seen placing either a backpack or a duffel bag on to the ground in the place where the second bomb went off in the moments leading up to that explosion. however, according to nbc news, that person has not been identified by name. they just see him on the tape and are working to identify him. he certainly has not been arrested or put into custody. police continue their work today to try to figure out exactly who that person is. last night, the fbi was planning to have one of their twice daily media briefings around 8:00 local time. that was canceled